1. Field of the Invention
The invention in general relates to conductivity cells and more particularly to a rugged cell for use in a hostile environment.
2. Description of the Prior Art
Conductivity cells for measuring the electrical conductivity of a fluid generally are comprised of two separated plates forming electrodes to which an electric potential is applied. By connecting the electrodes to a measuring circuit or device (such as a conductivity bridge or conductivity meter), the electrical conductance of a fluid introduced between the electrodes may be obtained.
Such structures are not conducive for use in a hostile environment. For example, as described in the aforementioned copending application in a steam turbine system, superheated steam often contains low concentrations of various impurities, one of which is sodium chloride. During the steam cycle operation, and due to the expansion of the steam in the low pressure section of the turbine it is possible that the entrained sodium chloride could form a saturated solution which if deposited upon the turbine rotor blades can lead to corrosion and cracking.
Conductivity sensors of the prior art are not adapted to measure conductivity in the hostile environment of an operational steam turbine. Further, the sodium chloride solution is deposited in the form of a thin film, the conductance of which cannot be measured by the spaced apart electrodes of the prior art conductivity cells.